95 lines
3.9 KiB
Prolog
95 lines
3.9 KiB
Prolog
/**
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Predicates for handling network sockets, both as a server and as a client.
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As a server, you should open a socket an call `socket_server_accept/4` to get a stream for each connection.
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As a client, you should just open a socket and you will receive a stream.
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In both cases, with a stream, you can use the usual predicates to read and write to the stream.
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*/
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:- module(sockets, [socket_client_open/3,
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socket_server_open/2,
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socket_server_accept/4,
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socket_server_close/1,
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current_hostname/1]).
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:- use_module(library(error)).
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%% socket_client_open(+Addr, -Stream, +Options).
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%
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% Open a socket to a server, returning a stream. Addr must satisfy `Addr = Address:Port`.
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%
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% The following options are available:
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%
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% * `alias(+Alias)`: Set an alias to the stream
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% * `eof_action(+Action)`: Defined what happens if the end of the stream is reached. Values: `error`, `eof_code` and `reset`.
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% * `reposition(+Boolean)`: Specifies whether repositioning is required for the stream. `false` is the default.
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% * `type(+Type)`: Type can be `text` or `binary`. Defines the type of the stream, if it's optimized for plain text
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% or just binary
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%
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socket_client_open(Addr, Stream, Options) :-
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( var(Addr) ->
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throw(error(instantiation_error, socket_client_open/3))
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;
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true
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),
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must_be(var, Stream),
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must_be(list, Options),
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( Addr = Address:Port,
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atom(Address),
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( atom(Port) ; integer(Port) ) ->
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true
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;
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throw(error(type_error(socket_address, Addr), socket_client_open/3))
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),
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builtins:parse_stream_options(Options,
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[Alias, EOFAction, Reposition, Type],
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socket_client_open/3),
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'$socket_client_open'(Address, Port, Stream, Alias, EOFAction, Reposition, Type).
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%% socket_server_open(+Addr, -ServerSocket).
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%
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% Open a server socket, returning a ServerSocket. Use that ServerSocket to accept incoming connections in
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% `socket_server_accept/4`. Addr must satisfy `Addr = Address:Port`. Depending on the operating system
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% configuration, some ports might be reserved for superusers.
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socket_server_open(Addr, ServerSocket) :-
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must_be(var, ServerSocket),
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( ( integer(Addr) ; var(Addr) ) ->
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'$socket_server_open'([], Addr, ServerSocket)
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;
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Addr = Address:Port,
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must_be(atom, Address),
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can_be(integer, Port),
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'$socket_server_open'(Address, Port, ServerSocket)
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).
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%% socket_server_accept(+ServerSocket, -Client, -Stream, +Options).
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%
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% Given a ServerSocket and a list of Options, accepts a incoming connection, returning data from the Client and
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% a Stream to read or write data.
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%
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% The following options are available:
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%
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% * `alias(+Alias)`: Set an alias to the stream
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% * `eof_action(+Action)`: Defined what happens if the end of the stream is reached. Values: `error`, `eof_code` and `reset`.
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% * `reposition(+Boolean)`: Specifies whether repositioning is required for the stream. `false` is the default.
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% * `type(+Type)`: Type can be `text` or `binary`. Defines the type of the stream, if it's optimized for plain text
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% or just binary
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%
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socket_server_accept(ServerSocket, Client, Stream, Options) :-
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must_be(var, Client),
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must_be(var, Stream),
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builtins:parse_stream_options(Options,
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[Alias, EOFAction, Reposition, Type],
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socket_server_accept/4),
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'$socket_server_accept'(ServerSocket, Client, Stream, Alias, EOFAction, Reposition, Type).
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%% socket_server_close(+ServerSocket).
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%
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% Stops listening on that ServerSocket. It's recommended to always close a ServerSocket once it's no longer needed
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socket_server_close(ServerSocket) :-
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'$socket_server_close'(ServerSocket).
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%% current_hostname(-HostName).
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%
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% Returns the current hostname of the computer in which Scryer Prolog is executing right now
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current_hostname(HostName) :-
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'$current_hostname'(HostName).
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